Lifting device

ABSTRACT

A magnetic lifting device for rolls of strip steel, or the like. The device consists of a frame having a pair of electromagnets pivoted thereto. The electromagnets are hingedly connected at their inner ends so that they can assume a configuration in accordance with the contour of a steel roll or other object of magnetic material being lifted. Thus, the electromagnets can engage either the arcuate periphery of a roll of strip steel, or the flat end of the roll.

United States Patent Cecil J. Carter Hobart, Ind.

Jan. 31, 1969 Aug. 3, 1971 United States Steel Corporation inventor Appl. No. Filed Patented Assignee LII'TING DEVICE 1 Claim, 4 Drawing Figs.

U.S.Cl 294/655 Int. Cl 866: 1/04, B2lb 31/06 Field of Search .t 294/655, 88, MB CO, 113, 65; 214/1 BS, 658

[56] References Cited UNITED STATES PATENTS 3,040,921 6/1962 Davis 294/6545 X 3,147,872 9/1964 Olson .i 294/65 X Primary Examiner- Richard E Aegerter Assistant Examiner- Douglas D. Watts Attorney-Donald S. Ferito ABSTRACT: A magnetic lifting device for rolls of strip steel, or the like. The device consists of a frame having a pair of electromagnets pivoted thereto. The electromagnets are hingedly connected at their inner ends so that they can assume a configuration in accordance with the contour of a steel roll or other object of magnetic material being lifted. Thus, the electromagnets can engage either the arcuate periphery of a roll of strip steel, or the flat end of the roll.

PATENTED AUB 3:97:

IN V EN T01.

4 TTOE'NE vs.

LIFTING DEVICE This invention relates to lifting devices, and more particularly to a magnetic lifting apparatus specifically intended to handle objects of irregular contour, such as rolls of strip steel.

A main object of the invention is to provide a novel and improved magnetic lifting apparatus particularly adapted for lifting objects of irregular shape, such as rolls of strip steel, or the like, the lifting device being simple in construction, and being adaptable so as to conform to the contour of the surface engaged thereby.

A further object of the invention is to provide a novel and improved magnetic lifting device which is inexpensive to manufacture, which is durable in construction, which is adaptable to engage various objects of irregular shape, such as rolls of strip steel, or the like, and which is self-adjustable in accordance with the radius of curvature of the surface engaged by its lifting elements so as to most efficiently abut and support the object being lifted.

A still further object of the invention is to provide a novel and improved electromagnetic lifting apparatus specifically adapted for lifting rolls of strip steel, the apparatus being relatively compact in size, being easy to apply to a roll to be lifted, and having articulated magnetic elements which are self-adjusting so that they can conform either with the cylindrical contour of a roll of strip steel to engage the cylindrical surface of the roll, or alternatively, to conform with the flat planar configuration of the end edges of a rolled strip of steel, whereby to lift the roll with its axis vertical.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawing, wherein:

FIG. I is an elevational view of a magnetic lifting device constructed in accordance with the present invention, shown engaging the cylindrical surface of a roll of strip steel and indicating the manner in which the pivoted hinged electromagnets thereof conform with the contour of the cylindrical surface of the roll, whereby to allow the roll to be lifted with its axis substantially horizontal.

FIG. 2 is an elevational view similar to FIG. 1, but showing the articulated electromagnets of the device of FIG. 1 in coplanar position engaging the end of the roll of strip steel to be lifted, whereby the roll can be lifted with its axis in a vertical position.

FIG. 3 is a transverse vertical cross-sectional view taken substantially on the line 3-3 of FIG. 2.

FIG. 4 is an elevational view of a modified form of magnetic lifting device according to the present invention, wherein the pivoted electromagnets are not hingedly-connected together.

Referring to the drawing, and more particularly to FIGS. 1, 2 and 3, 11 generally designates a magnetic lifting device particularly adapted for lifting rolls of strip steel, or the like, for example, the roll of strip steel shown in dotted view at 12 in FIGS. 1 and 2. The lifting device 11 comprises a transverse bar member 13 of suitable rigid material, formed at its intermediate portion with an upstanding loop 14 adapted to be secured to the supporting hook or link element associated with a conventional lifting crane or similar equipment customarily employed for moving heavy objects, such as the steep strip rolls l2. Rigidly secured to and depending from the respective ends of the transverse bar member 13 are depending arms 15,15 of inverted V-shape, each of the arms having the respective downwardly diverging segments 16 and 17. Pivoted between the arms for example, at pivots 18, is a first electromagnet 19 having the downwardly facing flat pole pieces 20. Designated at 21 is a second electromagnet which is slidably and pivotally connected to and supported between the arm segments 17. For example, the arm segments 17 may be provided with slots 22 through which extend pivot pins 23 projecting from opposite sides of electromagnet 21, whereby the pins 23 cooperate with the slots 22 to define a sliding pivotal connection therewith.

The inner bottom corners of the electromagnet assemblies 19 and 21 are hingedly connected together at 24 so that the electromagnets 19 and 21 can rotate relative to each other. For example, from the coplanar position shown in FIG. 2, to the angled position shown in FIG. 1.

The electromagnet 21 is provided with the flat downwardly facing pole pieces 25, similar to the pole pieces 20 of the firstdescribed electromagnet 19. Thus, the electromagnets 19,21 may engage either the cylindrical surface of the roll of strip steel 12, allowing the roll to be supported by the device with its axis in a horizontal position, or alternatively, may be engaged at the end of the roll with the electromagnets 19 and 21 in coplanar position, as shown in FIG. 2, allowing the roll to be supported by the device with its axis in a vertical position.

To limit the rotation of the electromagnets l9 and 21, a pair of outwardly projecting stop lugs 27 is provided on the first electromagnet 19, engageable with the top edge of the arm segment 16 in the manner shown in FIG. 2, and a similar pair of outwardly projecting stop lugs 28,28 are provided on the second electromagnet 21, engageable with the top edges of the arm segments 17,17 in the manner shown in FIG. 2. In this manner, the electromagnets 19 and 21 are limited in their swinging movement toward each other from the angular positions of FIG. 1 to the coplanar positions of FIG. 2, so that they are limited to a position wherein their downwardly facing pole pieces 20 and 25 are substantially coplanar and can efficiently engage the horizontal top end of the roll 12. At the same time, the articulated electromagnets 19 and 21 can swing freely so as to conform with the cylindrical contour of a roll 12 when the roll is to be engaged with its axis in a horizontal position, as in FIG. 1, and the electromagnets are self adjustable to conform with different sizes of rolls.

In the embodiment illustrated in FIG. 4, the electromagnets shown at 19' and 21' are pivotally connected to the arm segments 16' and 17' at respective pairs of pivot points 18' and 23', but the electromagnets are not hingedly connected together at their inner lower corners, as in the embodiment illustrated in FIGS. 1, 2 and 3. As in the previously described form of the invention, namely, the embodiment of FIGS. 1, 2 and 3, the electromagnets are provided with outwardly projecting pairs of stop lugs 27 and 28, engageable with the top edges of the arm segments 16' and 17' to limit the inward swinging movement of the electromagnets toward each other to positions wherein their downwardly facing pole pieces 20 and 25 are substantially coplanar and horizontal, as shown in full-line view in FIG. 4. The electromagnets 19' and 21 are further provided with bottom pairs of stop lugs 30 and 31 engageable with the bottom edges of the arm segments 16' and 17' to limit the outward swinging movements of the electromagnets 19' and 21 for example, to the dotted-view positions of the electromagnets shown in FIG. 4. There is thus provided a substantial range of self-adjustment of the electromagnets 19' and 21 which enables them to readily conform to a wide range of variation of the radius of curvature of the objects to be lifted by the device.

In both of the forms of the invention above described, namely, the form of FIGS. 1, 2 and 3, and the modification of FIG. 4, the electromagnets are biased by their weight so that they will normally assume the horizontally aligned positions shown respectively in FIG. 2 and in FIG. 4. Thus, in the normal position of the electromagnets represented in FIG. 2, the lugs 27 and 28 engage the top edges of the arm segments 16 and 17 to support the electromagnets in their normal positions and, similarly, in the modification of FIG. 4, the lugs 27 and 28 engage the top edges of the arm segments 16' and 17 to support the electromagnets 19' and 21' in their horizontally aligned positions. As above-explained, the electromagnets are free to angle relative to each other, for example, to the positions of FIG. 1, or to the dotted-view positions of FIG. 4, in accordance with the nonplanar configuration of the object received beneath the electromagnets and supported thereby.

It will be noted that in both of the above-described embodiments of the invention, namely, the embodiment of FIGS. 1, 2

and 3, and the embodiment of FIG. 4, the electromagnets are pivoted on parallel axes so that they can readily adjust themselves to receive the cylindrical curvature of a roll of strip steel, or similar material, for example, the roll 12, within the limits of their permitted angular movements. Within such limits, as shown for example, in FIG. 1, the pole faces 20 and 25 of the electromagnets can assume positions abutting the periphery of the roll and arranged substantially tangent thereto. The holding device 11 is thus allowed to present an inverted V-shaped configuration to the cylindrical object to be 7 supported, with the configuration being.selfvadjusting to provide a magnetic holding effect of maximum efficiency.

While certain specific embodiments of an improved magnetic lifting device have been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

lclaim:

l. A magnetic lifting device comprising a supporting frame,

said frame having opposed pairs of downwardly diverging arms, means for attaching the frame to .a supporting cable or the like, for suspending the frame, a pair of magnets pivotally connected to the bottom portion of the frame between said opposing arms on spaced axes and facing downwardly, said magnets being spaced apart sufficiently to allow them to angle relative to each other so as to be capable of receiving therebeneath an object of magnetic material to be lifted, said magnets having bottom pole faces adapted to abut the surface of the object substantially tangentially thereof, stop means limiting angling movement of said magnets on said spaced axes, said stop means comprising projections on the magnets engageable with edge portions of the frame, said projections on said magnets being located so as to engage top edge portions of said arms and being arranged so as to limit rotation of the magnets to positions wherein the pole faces are substantially coplanar, and means hingedly connecting the inner end portions of the magnets with the hinge axis located parallel to the pivotal axes of the magnets and adjacent the lower inner corner portions of the magnets. 

1. A magnetic lifting device comprising a supporting frame, said frame having opposed pairs of downwardly diverging arms, means for attaching the frame to a supporting cable or the like, for suspending the frame, a pair of magnets pivotally connected to the bottom portion of the frame between said opposing arms on spaced axes and facing downwardly, said magnets being spaced apart sufficiently to allow them to angle relative to each other so as to be capable of receiving therebeneath an object of magnetic material to be lifted, said magnets having bottom pole faces adapted to abut the surface of the object substantially tangentially thereof, stop means limiting angling movement of said magnets on said spaced axes, said stop means comprising projections on the magnets engageable with edge portions of the frame, said projections on said magnets being located so as to engage top edge portions of said arms and being arranged so as to limit rotation of the magnets to positions wherein the pole faces are substantially coplanar, and means hingedly connecting the inner end portions of the magnets with the hinge axis located parallel to the pivotal axes of the magnets and adjacent the lower inner corner portions of the magnets. 